In the diagnosis and treatment of periodontal disease, a dentist typically will insert a probe into the gingival sulcus or periodontal pocket which surrounds a tooth, in an attempt to determine the depth of the periodontal pocket. Traditionally, the depth is determined through the mechanical sensing of the dentist as the probe tip touches the bottom wall surface of the pocket. In practice, it can be most difficult to determine the particular depth of the periodontal pocket and the bottom of the wall surface, when the tissue is diseased. A healthy gingiva has sufficient collageneous tissue at the bottom surface to resist penetration and, therefore, allow the depth to be determined easily by mechanical feel. However, where the periodontal pocket comprises diseased tissue, then the soft tissue may not resist penetration, and it can be penetrated easily by the tip of the probe without sufficient mechanical feel, to enable the dentist to determine the depth of the periodontal pocket. Therefore, it is most desirable to obtain an apparatus and a method by which the dentist or other examiners may determine accurately the depth of a periodontal pocket in the oral cavity of a patient.
In recent years, there has been a number of attempts to improve on the traditional periodontal probe. Gabathuler (15 Helv. Odont. Acta 114; 1971) has disclosed a pressure-sensitive probe, utilizing a piezoelectric crystal to determine the transcient forces applied during probing. While the Gabathuler probe allows more constant application of probing force, it does not improve upon the state-of-the-art technique of determining the bottom surface by mechanical feel and continues to rely on the user to apply manually the probing force.
Van der Velden (5 Journal of Clinical Periodontology 188; 1978) has disclosed a different type of pressure probe consisting of a plunger assembly connected to a variable air-pressure system. During probing, the plunger will intrude from the position of maximum extrusion only as the probing force exceeds the predetermined air pressure acting on the plunger. The distance at which the plunger is intruded can be read on a scale within the handle of the probe. While the van der Velden probe may allow for more accurate readings of pocket depth, it continues to rely on manual application of probing forces and does not overcome the problem of determining the bottom surface of the pocket, when the gingiva is soft or diseased.
Another periodontal probe system has been described in "Development of a Force Controlled Periodontal Probing Instrument", R. M. Vitek et al, J. Periodontal Research 14 93-94, 1979), wherein the probe instrument is moved by employing a spring-controlled system, but such a system does not include an end-point-indicating means.
Therefore, it is an object of my invention to provide a more accurate determination of pocket depth, even when the collageneous tissue of the pocket has deteriorated. It also is an object of my invention to provide a more constant application of probing force than can be applied ordinarily by manually held probes. Further, it is an object of my invention to provide means for mechanical or electrical determination of probe penetration to replace the traditional method of estimating the depth of penetration from visual observations. Additional objects and advantages of my invention will become apparent from the detailed disclosure that follows. It should be apparent that my invention may be utilized with appropriate modifications by those persons skilled in endodontistry for other applications, such as determining the depth of caries, root canals and fistulae.